I've played half a dozen games on the original Go, and I don't think I've used more than one rear button. In Half Life, it's more comfortable to hold for crouch. In one of the Spider Man games, it expected a trackpad click, which was easier to perform with a rear button.
Since games have been designed to be playable with only the face buttons, there's not always obvious utility for extras. Maybe as premium controllers become more popular, this will change. For now, I can definitely see the argument that 4 buttons are superfluous (except for standardization).
Even for emulators, they're great for binding all kinds of extra functions.
Using the right trackpad also means I can free up the right joystick for other stuff, and there's always enough other stuff I want to access regularly enough.
Rollercoaster Tycoon, FTL, point and click games are games the trackpad has vastly improved for me.
This reads like "I never play mouse driven games"
Like how ds4windows is used to translate Playstation controllers gryo and touchpad. Even the Steam controller requires Steam. I don't think oems are investing in the software to do the same.
It is how i got to play the original System Shock 2 on my Steam Deck even though the game was designed with a keyboard and mouse in place.
That's why distros like Bazzite and ChimeraOS have an additional translator[0] to take input events and output a controller that Steam supports, Dualsense edge or Steam Deck's controller, to be able to add support for gyro and back buttons.
[0] https://github.com/hhd-dev/hhd or https://github.com/ShadowBlip/InputPlumber
Lenovo's current handheld exposes an Xbox controller and a USB device with extra buttons. Handheld Daemon synthesizes them into a virtual PlayStaton controller. If you tried to use the current SteamOS without Handheld Daemon, the 6 extra buttons wouldn't work. The community is waiting to see if Valve ships a more robust solution that Linux can standardize on, or if we'll still be using daemons like HHD for devices that don't have official Valve support.
I think the Orange Pi Neo is the only (other) one that's targeting Linux only. And they do have touchpads
This is something to watch : we'll see how much Valve actually cares about Linux (and libre software/hardware in general) compared to just using it to get rid of Windows : will they make their new controller API SteamOS exclusive ?
(How well do Steam Link and Steam Controller work without Steam ?)
Steam Link the streaming application does require the Steam. Steam Link the discontinued hardware was able to run local applications without Steam.
The Steam Controller defaults to a keyboard and mouse mode until it receives a signal from Steam. So even on Linux, the Steam controller required Steam to function as a controller until the protocol was reverse engineered. Can read about it in the driver comment header, and the Valve copyright that didn't get added until they contributed support for the Deck controller in these drivers : https://github.com/torvalds/linux/blob/master/drivers/hid/hi...
(I recently started again regularly using both the hardware Steam Link and the original Steam Controller - funnily enough, for a non-Steam game - I'll have to check out what people have hacked over the years...)